/** @file
IA32 and X64 Specific relocation fixups

Copyright (c) 2004 - 2018, Intel Corporation. All rights reserved.<BR>
Portions Copyright (c) 2011 - 2013, ARM Ltd. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

--*/

#include <Common/UefiBaseTypes.h>
#include <IndustryStandard/PeImage.h>
#include "PeCoffLib.h"
#include "CommonLib.h"
#include "EfiUtilityMsgs.h"


#define EXT_IMM64(Value, Address, Size, InstPos, ValPos)  \
    Value |= (((UINT64)((*(Address) >> InstPos) & (((UINT64)1 << Size) - 1))) << ValPos)

#define INS_IMM64(Value, Address, Size, InstPos, ValPos)  \
    *(UINT32*)Address = (*(UINT32*)Address & ~(((1 << Size) - 1) << InstPos)) | \
          ((UINT32)((((UINT64)Value >> ValPos) & (((UINT64)1 << Size) - 1))) << InstPos)

#define IMM64_IMM7B_INST_WORD_X         3
#define IMM64_IMM7B_SIZE_X              7
#define IMM64_IMM7B_INST_WORD_POS_X     4
#define IMM64_IMM7B_VAL_POS_X           0

#define IMM64_IMM9D_INST_WORD_X         3
#define IMM64_IMM9D_SIZE_X              9
#define IMM64_IMM9D_INST_WORD_POS_X     18
#define IMM64_IMM9D_VAL_POS_X           7

#define IMM64_IMM5C_INST_WORD_X         3
#define IMM64_IMM5C_SIZE_X              5
#define IMM64_IMM5C_INST_WORD_POS_X     13
#define IMM64_IMM5C_VAL_POS_X           16

#define IMM64_IC_INST_WORD_X            3
#define IMM64_IC_SIZE_X                 1
#define IMM64_IC_INST_WORD_POS_X        12
#define IMM64_IC_VAL_POS_X              21

#define IMM64_IMM41a_INST_WORD_X        1
#define IMM64_IMM41a_SIZE_X             10
#define IMM64_IMM41a_INST_WORD_POS_X    14
#define IMM64_IMM41a_VAL_POS_X          22

#define IMM64_IMM41b_INST_WORD_X        1
#define IMM64_IMM41b_SIZE_X             8
#define IMM64_IMM41b_INST_WORD_POS_X    24
#define IMM64_IMM41b_VAL_POS_X          32

#define IMM64_IMM41c_INST_WORD_X        2
#define IMM64_IMM41c_SIZE_X             23
#define IMM64_IMM41c_INST_WORD_POS_X    0
#define IMM64_IMM41c_VAL_POS_X          40

#define IMM64_SIGN_INST_WORD_X          3
#define IMM64_SIGN_SIZE_X               1
#define IMM64_SIGN_INST_WORD_POS_X      27
#define IMM64_SIGN_VAL_POS_X            63

RETURN_STATUS
PeCoffLoaderRelocateIa32Image (
  IN UINT16      *Reloc,
  IN OUT CHAR8   *Fixup,
  IN OUT CHAR8   **FixupData,
  IN UINT64      Adjust
  )
/*++

Routine Description:

  Performs an IA-32 specific relocation fixup

Arguments:

  Reloc      - Pointer to the relocation record

  Fixup      - Pointer to the address to fix up

  FixupData  - Pointer to a buffer to log the fixups

  Adjust     - The offset to adjust the fixup

Returns:

  EFI_UNSUPPORTED   - Unsupported now

--*/
{
  return RETURN_UNSUPPORTED;
}


/**
  Pass in a pointer to an ARM MOVT or MOVW immediate instruction and
  return the immediate data encoded in the instruction

  @param  Instruction   Pointer to ARM MOVT or MOVW immediate instruction

  @return Immediate address encoded in the instruction

**/
UINT16
ThumbMovtImmediateAddress (
  IN UINT16 *Instruction
  )
{
  UINT32  Movt;
  UINT16  Address;

  // Thumb2 is two 16-bit instructions working together. Not a single 32-bit instruction
  // Example MOVT R0, #0 is 0x0000f2c0 or 0xf2c0 0x0000
  Movt = (*Instruction << 16) | (*(Instruction + 1));

  // imm16 = imm4:i:imm3:imm8
  //         imm4 -> Bit19:Bit16
  //         i    -> Bit26
  //         imm3 -> Bit14:Bit12
  //         imm8 -> Bit7:Bit0
  Address  = (UINT16)(Movt & 0x000000ff);          // imm8
  Address |= (UINT16)((Movt >> 4) &  0x0000f700);  // imm4 imm3
  Address |= (((Movt & BIT26) != 0) ? BIT11 : 0);  // i
  return Address;
}


/**
  Update an ARM MOVT or MOVW immediate instruction immediate data.

  @param  Instruction   Pointer to ARM MOVT or MOVW immediate instruction
  @param  Address       New address to patch into the instruction
**/
VOID
ThumbMovtImmediatePatch (
  IN OUT UINT16 *Instruction,
  IN     UINT16 Address
  )
{
  UINT16  Patch;

  // First 16-bit chunk of instruction
  Patch  = ((Address >> 12) & 0x000f);             // imm4
  Patch |= (((Address & BIT11) != 0) ? BIT10 : 0); // i
  *Instruction = (*Instruction & ~0x040f) | Patch;

  // Second 16-bit chunk of instruction
  Patch  =  Address & 0x000000ff;          // imm8
  Patch |=  ((Address << 4) & 0x00007000); // imm3
  Instruction++;
  *Instruction = (*Instruction & ~0x70ff) | Patch;
}

/**
  Pass in a pointer to an ARM MOVW/MOVT instruction pair and
  return the immediate data encoded in the two` instruction

  @param  Instructions  Pointer to ARM MOVW/MOVT instruction pair

  @return Immediate address encoded in the instructions

**/
UINT32
EFIAPI
ThumbMovwMovtImmediateAddress (
  IN UINT16 *Instructions
  )
{
  UINT16  *Word;
  UINT16  *Top;

  Word = Instructions;  // MOVW
  Top  = Word + 2;      // MOVT

  return (ThumbMovtImmediateAddress (Top) << 16) + ThumbMovtImmediateAddress (Word);
}


/**
  Update an ARM MOVW/MOVT immediate instruction instruction pair.

  @param  Instructions  Pointer to ARM MOVW/MOVT instruction pair
  @param  Address       New address to patch into the instructions
**/
VOID
EFIAPI
ThumbMovwMovtImmediatePatch (
  IN OUT UINT16 *Instructions,
  IN     UINT32 Address
  )
{
  UINT16  *Word;
  UINT16  *Top;

  Word = (UINT16 *)Instructions;  // MOVW
  Top  = Word + 2;                // MOVT

  ThumbMovtImmediatePatch (Word, (UINT16)(Address & 0xffff));
  ThumbMovtImmediatePatch (Top, (UINT16)(Address >> 16));
}


/**
  Performs an ARM-based specific relocation fixup and is a no-op on other
  instruction sets.

  @param  Reloc       Pointer to the relocation record.
  @param  Fixup       Pointer to the address to fix up.
  @param  FixupData   Pointer to a buffer to log the fixups.
  @param  Adjust      The offset to adjust the fixup.

  @return Status code.

**/
RETURN_STATUS
PeCoffLoaderRelocateArmImage (
  IN UINT16      **Reloc,
  IN OUT CHAR8   *Fixup,
  IN OUT CHAR8   **FixupData,
  IN UINT64      Adjust
  )
{
  UINT16      *Fixup16;
  UINT32      FixupVal;

  Fixup16   = (UINT16 *) Fixup;

  switch ((**Reloc) >> 12) {

  case EFI_IMAGE_REL_BASED_ARM_MOV32T:
    FixupVal = ThumbMovwMovtImmediateAddress (Fixup16) + (UINT32)Adjust;
    ThumbMovwMovtImmediatePatch (Fixup16, FixupVal);


    if (*FixupData != NULL) {
      *FixupData = ALIGN_POINTER(*FixupData, sizeof(UINT64));
      CopyMem (*FixupData, Fixup16, sizeof (UINT64));
      *FixupData = *FixupData + sizeof(UINT64);
    }
    break;

  case EFI_IMAGE_REL_BASED_ARM_MOV32A:
     // break omitted - ARM instruction encoding not implemented
  default:
    return RETURN_UNSUPPORTED;
  }

  return RETURN_SUCCESS;
}
